Stabilization of 1,1,1,trichloroethane with oxazole

ABSTRACT

1,1,1, TRICHLORETHANE, AN INDUSTRIAL SOLVENT, IS STABILIZED TO PREVENT ITS REACTION WITH METALS BY THE ADDITION THERETO OF FROM ABOUT 0.2 PERCENT TO 10 PERCENT OF A STABILIZING AGENT COMPRISING OXAZOLE EITHER ALONE OR IN COMBINATION WITH ONE OR MORE OTHER STABILIZERS HAVING A BOILING POINT IN THE RANGE FROM 40* C. to 200* C. and having a molecular structure which comprises at least one of the molecular groups consisting of ethylenic bond, acetylenic bond, acetal, ketone, alcohol, nitrile, amine, ester function, ether or tioether bond-bridge, nitrated group and 1,2epoxy group.

Unite States Vuillemenot 51 July 11, 1972 [54] STABHJZATION 0F1,1,1,TRICHLOROETHANE OXAZOLE [72] Inventor:

Jacques Vuillemenot, Uriage-les-Bains, France [30] Foreign ApplicationPriority Data Dec. 22, 1967 France ..67133564 [52] U.S. Cl ..252/153,252/171, 252/172, 252/364, 252/403, 260/652.5 [51] Int. Cl .C07d 17/40,Cl 1d 7/50, C23g 5/02 [58] FieldofSearch ..252/l53,162,170, 171,172,252/364, 403; 260/6525 [56] References Cited UNITED STATES PATENTS3/1970 Cormany et a]. ..260/652.5

Primary Examiner-Herbert B. Guynn Assistant Examiner-Dennis L. AlbrechtAttorneyPennie, Edmonds, Morton, Taylor and Adams 1 ABSI'RACT 1,1,1,trichlorethane, an industrial solvent, is stabilized to prevent itsreaction with metals by the addition thereto of from about 0.2 percentto 10 percent of a stabilizing agent comprising oxazole either alone orin combination with one or more other stabilizers having a boiling pointin the range from 40 C. to 200 C. and having a molecular structure whichcom prises at least one of the molecular groups consisting of ethylenicbond, acetylenic bond, acetal, ketone, alcohol, nitrile, amine, esterfunction, ether or tioether bond-bridge, nitrated group and 1,2-epoxygroup.

5Claims,NoDr-awings STABILIZATION OF 1,1,1,TRICHLOROETHANE W'ITH OXAZOLEBACKGROUND OF THE INVENTION I. Field of the Invention This inventionrelates to a method for the stabilization of 1,1,1, trichlorethane andthe product produced thereby. In particular, it relates to thestabilization of 1,1 ,l, trichlorethane, an industrial solvent, by theaddition thereto of oxazole, either alone or in combination with otherstabilizing agents.

II. Description of the Prior Art 1,1,1, trichlorethane, ormethylchloroform, is an industrial solvent having high dissolving powerand flame-resistant properties; it is used as a propellant in aerosolsand also for degreasing metallic pieces. Despite its excellentproperties as an industrial solvent, 1,1,1, trichlorethane has theserious limitation of being much more reactive with respect to metalsthan other chlorinated hydrocarbons such as chloroform, carbontetrachloride, trichlorethylene or perchlorethylene. This reactivity isparticularly important with respect to light metals such as aluminum,magnesium or their alloys and results in a rapid attack on the metal anda strong decomposition of the solvent.

In order to lessen its reactivity, stabilizing substances have beenadded to 1,1,1, trichlorethane; generally, these substances, which areeffective with other chlorinated hydrocarbons, have a very poorefficiency with respect to 1,1,1, trichlorethane. Specifically, nostabilizing substance heretofore known has been capable ofsatisfactorily stabilizing this compound when it is in contact withaluminum. The present invention provides a material which effectivelyand efficiently stabilizes 1,1,1, trichlorethane. This stabilizing agentwhich is comprised of oxazole, either alone or in combination withcertain other stabilizing agents, has been found to effectivelystabilize 1,1,1, trichlorethane even when the latter is at its boilingtemperature and in contact with aluminum.

SUMMARY OF THE INVENTION The present invention is based on the discoverythat 1,1,1, trichlorethane, an industrial solvent which is an effectivedegreasing agent, can be stabilized against reaction with light metalssuch as aluminum, magnesium or their alloys with the resultantdecomposition of the solvent, by the addition thereto of oxazole, eitherby itself or in combination with certain other stabilizing agents.Broadly stated, this invention comprises the stabilization of 1,1,1,trichlorethane by the addition thereto of from about 0.2 percent topercent of a stabilizing agent which comprises oxazole, either by itselfor in combination with one or more other stabilizers having a boilingpoint in the range from 40 C. to 200 C. and having a molecular structurewhich comprises at least one of the molecular groups consisting ofethylenic bond, acetylenic bond, acetal, ketone, alcohol, nitrile,amine, ester functions, ether or tioether bondbridge, nitrated group and1,2-epoxy group Oxazole is a colorless liquid with a boiling point of 69C. 70 C. under 760 mm. Hg, a relative density d25/4=1.0,808 and arefractive index 1,25/D= 1.4,245. Oxazole has a structural formula asfollows:

CHN iii: iii;

The stabilizing agent in accordance with this invention is added to1,1,1, trichlorethane in an amount which may vary from 0.2 percent to 10percent by weight. However, concentrations varying from between 2percent to 6 percent by weight are preferable. These weight percentagesof the stabilizing agent include both the oxazole and any othercomponents thereof. Within the stabilizing agent itself, the oxazolecontent may vary from between 1 percent and 99 percent by weightthereof. As previously stated, the stabilizing agent may containstabilizers other than Oxazole; however, these should be chosen fromamong stabilizing compounds which have a boiling point in the range from40 C. to 200 C. and preferably between 50 C. and C.

The stabilizing agent of the present invention, when added to 1,1,1,trichlorethane, results in a stabilized solvent which is not only stableagainst a reaction with metals but is also storage stable.

DESCRIPTION OF THE PREFERRED PRACTICE OF THE INVENTION The stabilizingagent of the present invention comprises oxazole, either by itself or incombination with certain other stabilizers such as, for example,1,2-epoxy butane, nitromethane, tertiary butanol and ethyl acetate. Thestabilizing agent may be added to the 1,1,1, trichlorethane(methylchloroform) in an amount varying from between about 0.2 percentto 10 percent by weight thereof but is preferably added in an amount offrom about 2 percent to 6 percent by weight. The efficiency ofstabilization of the system with respect to the 1,1,1, trichlorethane isdetermined by means of the test used by the National Institute of DryCleaners, 3-55 specification, which Was perfected for use with thecompound trichlorethylene.

The aforesaid test comprises the introduction of ml. of puremethylchloroform and a stabilizing agent into a 300 ml. flask surmountedby a Soxhlet extractor, having a volume of approximately 70 ml., and acooling condenser, Allihn bulb type, having a pickling brine circulationat -1 5 C. The flask is adapted to include a tapered tube through whichwet air is allowed to enter, while the gases evolving at the top of theAllihn cooling condenser are sent into an Erlenmeyer flask containingpure water. Lastly a lOO-watt lamp is placed a few cen timeters from thevapor top in the Soxhlet extractor.

Three aluminum plates are then introduced into the system, the first isplaced into the flask, the second into the bottom of the Soxhlet and thethird plate is suspended at the lower part of the cooling condenser sothat solvent vapors condense on this plate. All of the plates, which areidentical, are 50 mm. X 10 mm. X 3 mm. in size and have a lengthwisegroove of l X 1 mm. on one side thereof.

The stabilization test comprises raising the stabilizing agent to betested to the boiling point for 48 hours while adjusting the heat inputso as to cause the composition to flow back at such a rate that theextractor empties every 8-10 minutes. F 01- lowing this procedure,analyses are carried out to determine the quantity of acid (expressed inHCl) in the flask, determination of the quantity of acidity (expressedin HCl) in the Erlenmeyer flask, and a physical evaluation of theappearance of the aluminum plates.

EXAMPLES With respect to the stabilization efiiciency test describedabove, the following stabilizing agents were tested:

x Comparison test The foregoing tests produced the following results:

Aluminum plates it Comparison Test xx After a minute heating. The platesin the Soxhlet and the cooling condenser have not been in contact withthe solvent.

While the invention has been described hereinabove in terms of a numberof examples of the process thereof and the product produced thereby, theinvention itself is not limited thereto, but rather comprehends allmodifications of and departures from those examples properly fallingwithin the spirit and scope of the appended claims.

I claim:

1. An industrial solvent consisting essentially of a mixture of1,1,1-trichloroethane and from about 0.2 percent to about 10 percent byweight based on said 1,1,l-trichloroethane, of a stabilizing compositionconsisting essentially of:

a. from 1 to 100 percent of oxazole by weight of said stabilizingcomposition; and

b. from 0 to 99 percent by weight of said stabilizing composition, of astabilizing agent selected from the group consisting of1,2-epoxy-butane, nitromethane, tertiary butanol, ethyl acetate, andmixtures thereof.

2. An industrial solvent according to claim 1 wherein 2 to 6 percent of1,1,1-trichloroethane by weight consists essentially of the stabilizingcomposition.

3. An industrial solvent according to claim 1 wherein the stabilizingcomposition contains 5 percent to percent oxazole by weight of saidstabilizing composition.

4. An industrial solvent according to claim 1 wherein the stabilizingcomposition consists essentially of:

a. from I to 99 percent of oxazole by weight of said stabilizingcomposition; and

b. from 1 to 99 percent by weight of said stabilizing composition, of acompound selected from the group consisting of nitromethane, l, 2 epoxybutane, ethyl acetate, and mixtures thereof.

5. An industrial solvent according to claim 1 wherein the stabilizingcomposition consists essentially of:

a. from 1 to 99 percent of oxazole by weight of said stabilizingcomposition; and

b. from 1 to 99 percent by weight of said stabilizing composition ofacompound selected from the group consist ing of nitromethane, l, 2-epoxy butane, tertiary butanol and mixtures thereof.

2. An industrial solvent according to claim 1 wherein 2 to 6 percent of1,1,1-trichloroethane by weight consists essentially of the stabilizingcomposition.
 3. An industrial solvent according to claim 1 wherein thestabilizing composition contains 5 percent to 95 percent oxazole byweight of said stabilizing composition.
 4. An industrial solventaccording to claim 1 wherein the stabilizing composition consistsessentially of: a. from 1 to 99 percent of oxazole by weight of saidstabilizing composition; and b. from 1 to 99 percent by weight of saidstabilizing composition, of a comPound selected from the groupconsisting of nitromethane, 1, 2 - epoxy - butane, ethyl acetate, andmixtures thereof.
 5. An industrial solvent according to claim 1 whereinthe stabilizing composition consists essentially of: a. from 1 to 99percent of oxazole by weight of said stabilizing composition; and b.from 1 to 99 percent by weight of said stabilizing composition of acompound selected from the group consisting of nitromethane, 1, 2-epoxy - butane, tertiary butanol and mixtures thereof.